1. Field of Invention
This invention relates to structures, specifically to commercial buildings that provide demand side management energy savings, and improved fire safety.
2. Description of Prior Art
There is a great need and public support for improving the energy efficiency in the United States. Commercial buildings account for one-sixth of national energy consumption and 32% of electricity use, yet roof R values average about 10 for most small and medium size structures.
In general, insulation ratings are compromised in systems buildings by compression of insulation at metal purlins. This degrades the already low insulation value installed because of cost considerations. Other factors are the tenuous vapor barrier of insulation facing and the practice of stapling seams of facing together contribute to eventual condensation, further degradation of R—value and corrosion on the underside of the roof deck.
A number of workers, such as Clemenson (U.S. Pat. No. 4,738,072), Sparkes (U.S. Pat. No. 4,875,320), and Bolich (U.S. Pat. No. 5,724,780) have attempted to solve compression of insulation by techniques to encapsulate the metal purlins and expand the insulation to its full thickness with supporting structures. These systems add complexity and cost to an already tedious construction system with multiple passes across the roof deck during installation. They do not improve the R—value of fiberglass insulation and do not address basic problem of the metal purlins introducing a thermal short circuit.
One approach to insulation improvement is the use insulating gas mixtures as typically used in windows and some foams, example Rotermund (U.S. Pat. No. 5,965,231). To date, it has not been used extensively with conventional fiberglass insulation.
Another approach to solving insulation problems has been to utilize structural insulated panels with foam cores as typified by Sauer (U.S. Pat. No. 3,760,548). These systems are yet more expensive, and rarely used to replace the purlins; structural properties are not used effectively. They are universally attached to the structure with self-drilling screws that pass through the joints between panels. Problems arise from roof leakage. These are only partially solved with additional labor intensive steps in construction.
The tight barrier and heat reflective roofing often causes rapid flashover in a building fire. The organic foam insulation contributes large amounts of smoke. It can also occasionally melt or decompose, passing through holes in the roof deck and adding combustibles to a second phase of the fire. Fire fighters reaching a blaze typically need to chop a hole in the roof deck to locate the fire and to begin fighting it. These problems are generally even more accentuated in flat roof buildings.
A number of workers have attempted to deal with these fire fighting issues. Shapiro (U.S. Pat. No. 5,483,956) and Smith (U.S. Pat. No. 5,027,741) have devices for aiding in escape from a smoke filled environment. Welch (U.S. Pat. No. 5,927,990) and Astell (U.S. Pat. No. 6,114,948) deal with aiding fire fighters in smoke and flashover situations. L'Heureux (U.S. Pat. No. 5,165,659) improves on methods for opening up shingle/plywood roofs in fires. None of these approaches deal with the basic problems, which are heat and smoke containment and contribution of combustibles from the roof deck.
Sprinklers are an alternative approach that is not often used in small to medium sized buildings because of initial cost, complexity, and difficulty of maintenance. Walls (U.S. Pat. No. 6,003,609) attempts to solve this through a ceiling/roof mounted modular device using fire-retardant chemical released by a fusable link. Anghinetti (U.S. Pat. No. 4,104,834), Morris (U.S. Pat. No. 6,161,348), Veen (U.S. Pat. No. 3,788,013) and Lyons (U.S. Pat. No. 5,960,596) are among a large group of fire vents that release smoke and heat from fires. Some of the factors limiting use of these measures are again cost, inability locate them in the area of the fire, and effective weatherproofing of the roof membrane.
Lighting is one of the highest operating costs for many retail operations. More than 50% of commercial/industrial buildings could use daylighting to cut energy costs, but do not. This may be due to a lack of effective daylighting panels to control lighting and heat buildup, while producing a weatherproof roof deck assembly. This is particularly true of sloped roof metal buildings.
Gumpert (U.S. Pat. No. 5,323,576) has a skylight suited to standing seam roofing, but it has no attenuating or control capability. Christopher (U.S. Pat. No. 5,617,682) and Curshod (U.S. Pat. No. 5,204,777) have light attenuators, but lack an effective means for dissipating heat buildup in the panel. They do not have adequate means for assembling their panels into commercial roofing. Dittmer (U.S. Pat. No. 5,062,247) has a passive heat dissipation system for his panel, but lacks an active daylighting control system.
Many commercial heating and cooling systems have poor efficiency as they work using air source heat pumps having a heating coefficient of performance of 2.2-2.8 and a cooling EER as low as 12. One of the most successful innovations in the HVAC field has been the development and use of (geothermal) ground water heat pumps that can achieve a heating coefficient of performance of 4.5 to 5 and a cooling EER of 20. Such systems are limited, however, by cost of wells and limitations on the availability or suitability of a groundwater source for the heat pumps.
Many integral solar panels built into a roof structure in the prior art have been designed from the standpoint of using glass glazing on a wooden roof structure. Provisions for air or water circulation to the panels and integration into a complete energy management system have been limited. The use of wood and the residential construction methods do not closely match the needs of commercial and light industrial structures. The goal of using solar energy to provide direct heat requires large amounts of storage, high collection temperatures and often duplication of heating equipment to serve as backup. Stout, (U.S. Pat. No. 4,244,355), is typical of this group of prior art.
Wilhelm, (U.S. Pat. No. 4,327,707), utilized a low cost film based collector for retrofit to existing roofs. Though efficient, the invention does not address the distribution system for feeding working fluid to panels through the roof deck. The fundamental drawback of nearly all the prior solar collector art is the lack of a fluid circulation system that moves working fluid to the exterior of the roof deck without sacrificing leak integrity of the roof. Hartman, (U.S. Pat. No. 5,134,827), utilized a good fluid transfer system with a low cost film collector, but did not provide a very good connection to the building frame. A second limitation of most prior solar art is the use of unusual construction methods that do not fit the general skills, training and work habits common in the trades.
In general, the owner or user sees the roof of a typical commercial or industrial building as a liability rather than an advantage.